JP2023097022A - Seat back frame and vehicle seat - Google Patents

Abstract

To achieve both retention of a seated person's posture during normal running of a vehicle and protection of the seated person in the event of a rear surface collision of a vehicle.SOLUTION: A seat back frame 32 includes: left and right side frames 34 extending in a seat vertical direction in left and right side parts of a seat back 30 of a vehicle seat 10; a lower panel 40 (a lower frame) bridged between rear ends of lower end parts of the left and right side frames 34; and a sacrum supporting part 42 extending from the lower end of the lower panel 40 to a seat front side and supporting the sacrum part of a seated person from a seat rear side. The sacrum support part 42 is provided with a bending portion 42B1 (a fragile site) that is weakened against a load from the seat front side.SELECTED DRAWING: Figure 1

Description

The present invention relates to a seat back frame and a vehicle seat.

In the seat disclosed in Patent Document 1, a pair of side frames are provided on both sides in the seat width direction of a seatback frame that constitutes the skeleton of the seatback. A sacral supporting member that supports the sacral part of the seated person is laid across the pair of side frames. As a result, the rocking motion of the seated person in the roll direction during vehicle travel is suppressed, and the seating posture is stabilized.

In the seatback frame disclosed in Patent Document 2, a rear panel (lower frame) made of sheet metal spans between the rear end portions of the lower portions of the left and right side frames. The lower frame has a concave-convex shaped portion that is bent so that concaves and convexes are alternately arranged in the seat width direction. When an excessive load is applied to the lower frame from the occupant during a rear-end collision of the vehicle, the concave-convex portion expands. As a result, the load is dispersed, and the tensile load applied to the fixed portions of the lower frame and the left and right side frames is reduced. As a result, it is possible to prevent or suppress damage to other members such as the fixing portion and the left and right side frames.

Japanese Patent No. 6364309 Japanese Patent No. 6387258

The prior art described in Patent Document 1 does not take into consideration the protection of the seated occupant in the event of a rear-end collision of the vehicle. On the other hand, in the prior art described in Patent Literature 2, no consideration is given to maintaining the posture of a seated person during normal vehicle travel.

In view of the above facts, the present invention aims to provide a seat back frame and a vehicle seat that are capable of both maintaining the posture of the occupant during normal vehicle travel and protecting the occupant in the event of a rear-end collision of the vehicle. aim.

The seat back frame according to the invention of claim 1 is hung between the left and right side frames extending in the vertical direction of the seat within the left and right side portions of the seat back of the vehicle seat and the lower end portions of the left and right side frames. a passed lower frame, and a frailty that extends from the lower end of the lower frame to the front side of the seat, supports the sacral part of the seated person from the rear side of the seat, and is weakened against the load from the front side of the seat. a sacral support having a portion thereon.

In the seatback frame according to claim 1, the left and right side frames extend in the vertical direction of the seat within the left and right side portions of the seatback of the vehicle seat. A lower frame spans between the lower ends of the left and right side frames. A sacral supporting portion extends forward of the seat from the lower end portion of the lower frame. The sacrum support portion supports the sacral portion of the seated person from the rear side of the seat. As a result, the rocking motion of the seated person in the roll direction during normal vehicle travel is suppressed, and the seated posture is maintained. The sacral supporting portion is provided with a weakened portion weakened against a load from the front side of the seat. Therefore, in the event of a rear-end collision of the vehicle, the sacrum support portion is deformed at the fragile portion by inputting a load from the sacrum portion of the seated person to the sacrum support portion. This absorbs the inertial energy of the seated person and reduces the moment applied to the seatback frame. As a result, the occurrence of a phenomenon in which the seated occupant climbs up obliquely upward in the rear of the vehicle is suppressed, so that the seated occupant can be protected.

According to a second aspect of the present invention, there is provided a seat back frame according to claim 1, wherein the sacrum supporting portion is made of sheet metal, and a fixing portion fixed to the lower surface of the lower frame; and a front extending portion that extends forward, and the fragile portion is provided at an intermediate portion in the seat front-rear direction of the front extending portion.

In the seatback frame according to claim 2, the sacrum supporting portion made of sheet metal has a fixing portion and a forward extending portion. The fixed portion is fixed to the lower surface of the lower frame, and the forward extending portion extends from the fixed portion toward the front side of the seat. In the event of a rear-end collision of the vehicle, the fragile portion provided in the intermediate portion of the forward extension portion in the longitudinal direction of the seat is deformed by the load from the sacral region of the seated person. In this way, since the fragile portion is provided in the forward extending portion of the sheet metal sacral support, the degree of freedom in setting the shape of the fragile portion is high, and the deformation load of the fragile portion can be easily adjusted.

The seat back frame according to the invention of claim 3 is the seat back frame according to claim 2, wherein the fragile portion is formed such that an intermediate portion in the seat front-rear direction of the forward extending portion is bent to form a protrusion to one side in the seat up-down direction. It has a bend.

In the seatback frame according to claim 3, the sacrum supporting portion made of sheet metal has the fixing portion and the forward extending portion described above. An intermediate portion of the forward extending portion in the seat front-rear direction is provided with a bent portion as a fragile portion that is bent to form a protrusion toward one side in the seat up-down direction. In the event of a rear-end collision of a vehicle, stress concentrates on the bent portion due to the load from the sacrum of the seated person, and the bent portion deforms (buckles). In this way, since the bent portion is the fragile portion, the fragile portion can have a simple configuration.

According to a fourth aspect of the present invention, there is provided a seat back frame according to the second or third aspect, wherein the fragile portion is formed with a through-hole penetrating the fragile portion in the vertical direction of the seat.

In the seatback frame according to claim 4, the sacrum supporting portion made of sheet metal has the fixing portion and the forward extending portion described above. A fragile portion provided at an intermediate portion in the seat front-rear direction of the forward extending portion is formed with a through hole passing through the fragile portion in the seat vertical direction. The deformation load of the fragile portion can be easily adjusted by changing the setting of the shape, number, etc. of the through-holes.

The seat back frame according to the invention of claim 5 is the seat back frame according to any one of claims 2 to 4, wherein the sacral supporting portion extends from the front end of the forward extending portion to one side in the vertical direction of the seat. It has a protruding longitudinal extension.

In the seatback frame according to claim 5, the sacrum supporting portion made of sheet metal has the fixing portion, the forward extending portion, and the longitudinal extending portion. The longitudinal extension extends from the front end of the front extension to one side in the vertical direction of the seat. Since the sacral region of the seated person is supported by the front surface of the longitudinally extending portion, the sense of discomfort of the seated person is reduced.

According to a sixth aspect of the present invention, there is provided a seat back frame according to any one of the first to fifth aspects, wherein a reclining rod is bridged between the lower end portions of the left and right side frames, and the The sacral support is arranged below the seat with respect to the reclining rod.

In the seatback frame according to claim 6, the reclining rod is bridged between the lower ends of the left and right side frames. A sacral supporting portion extending forward from the lower end of the lower frame is arranged below the seat with respect to the reclining rod. By arranging the sacrum support portion at this height, the sacral portion of the seated person can be appropriately supported.

According to a seventh aspect of the present invention, there is provided a vehicle seat in which a seat cushion has a seat cushion frame, and lower ends of the left and right side frames are connected to a rear end of the seat cushion frame. A seat back having the seat back frame according to any one of items 6.

In the seat back frame according to claim 7, the lower end portions of the left and right side frames of the seat back frame are connected to the rear end portion of the seat cushion frame of the seat cushion. Since the seat back frame described above is described in any one of claims 1 to 6, the above-described functions and effects can be obtained.

As described above, the seat back frame and the vehicle seat according to the present invention can both maintain the posture of the seated person during normal vehicle travel and protect the seated person during a rear-end collision of the vehicle.

1 is a perspective view showing a vehicle seat according to an embodiment; FIG. It is a front view showing the seat back frame according to the embodiment. It is a bottom view which shows the same seat back frame. FIG. 4 is a plan view of a sacrum support bracket included in the seat back frame; It is a front view of the same sacral support bracket. Fig. 3 is a side view of the same sacral support bracket; FIG. 3 is a side view showing a partial configuration of a vehicle seat according to a comparative example; FIG. 4 is a side view showing a partial configuration of a vehicle seat according to a comparative example, showing a state of the vehicle at the beginning of a rear-end collision; FIG. 9 is a side view corresponding to FIG. 8, showing a state after some time has passed from the state shown in FIG. 8; FIG. 10 is a side view corresponding to FIGS. 8 and 9, showing a state after some time has passed from the state shown in FIG. 9; FIG. 11 is a side view showing the state of the vehicle seat and the seated person in the state shown in FIG. 10; FIG. 2 is a side view showing a partial configuration of the vehicle seat according to the embodiment, showing a state at the beginning of a rear-end collision of the vehicle. FIG. 13 is a side view corresponding to FIG. 12, showing a state in which some time has passed since the state shown in FIG. 12; FIG. 14 is a side view corresponding to FIGS. 12 and 13, showing a state in which some time has passed since the state shown in FIG. 13; FIG. 15 is a side view showing the state of the vehicle seat and the seated person in the state shown in FIG. 14;

A seatback frame 32 and a vehicle seat 10 according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 15. FIG. It should be noted that some reference numerals may be omitted in each drawing for the purpose of making the drawings easier to see. An arrow FR indicated appropriately in each figure indicates the front of the vehicle, an arrow UP indicates the upper side of the vehicle, and an arrow RH indicates the right side of the vehicle. In the following description, front, rear, left, right, up, and down directions refer to front and rear in the longitudinal direction of the vehicle, left and right in the left and right direction of the vehicle (width direction of the vehicle), and up and down in the vertical direction of the vehicle, unless otherwise specified.

As shown in FIG. 1, the vehicle seat 10 according to this embodiment includes a seat cushion 12, a seat back 30, and a headrest 56. As shown in FIG. The seat cushion 12 supports the buttocks and thighs of the seated person, the seat back 30 supports the waist and back of the seated person, and the headrest 56 supports the head of the seated person. The seat cushion 12 has a seat cushion frame 14 which is a skeleton member, the seat back 30 has a seat back frame 32 which is a skeleton member, and the headrest 56 has a headrest frame (illustration) which is a skeleton member. omitted). Note that FIG. 1 schematically illustrates the vehicle seat 10 .

Pad materials (not shown) covered with skins 22, 54, 58 are attached to the seat cushion frame 14, the seat back frame 32, and the headrest frame, respectively. The front-back direction, left-right direction (width direction), and up-down direction of the vehicle seat 10 coincide with the front-rear, left-right, up-down directions of the vehicle.

The seat cushion frame 14 includes a pair of left and right side frames 16 extending in the seat front-rear direction on the left and right side portions of the seat cushion 12, and a front frame 18 that spans between the upper ends of the front portions of the left and right side frames 16. and a rear frame 20 that spans between the rear ends of the left and right side frames 16 . A seat cushion spring (not shown) is bridged between the front frame 18 and the rear frame 20 . The seat cushion spring elastically supports the pad material of the seat cushion 12 from the lower side of the seat.

The left and right side frames 16 are formed in an elongated shape by, for example, press-molding a sheet metal, and are arranged with the longitudinal direction along the seat front-rear direction and the thickness direction along the seat width direction. The front frame 18 is formed of, for example, sheet metal in a substantially rectangular shape, and is disposed so that its thickness direction extends along the seat vertical direction. fixed by means. The rear frame 20 is formed of, for example, a metal pipe, and is arranged with its axial direction along the seat width direction. is rotatably connected to the

The left and right side frames 16 are connected to the floor of the vehicle body via a known seat slide mechanism 24, and are adjustable in position relative to the floor of the vehicle in the longitudinal direction of the vehicle. A seatback frame 32 is connected to the rear ends of the left and right side frames 16 via a well-known reclining mechanism 26 so as to be reclinable. In this embodiment, the front, rear, left, right, top, and bottom directions of the seat back 30 indicate the directions when the seat back 30 stands up with respect to the seat cushion 12 .

As shown in FIGS. 1 to 3, the seatback frame 32 includes a pair of left and right side frames 34 extending in the seat vertical direction (the height direction of the seatback 30) on the left and right sides of the seatback 30, An upper frame 36 bridged between the upper ends of the left and right side frames 34, an upper panel 38 fixed to the upper frame 36, and a lower panel 40 bridged between the rear ends of the lower ends of the left and right side frames 34. and a sacrum support bracket 42 extending from the lower end of the lower panel 40 to the front side of the seat. The lower panel 40 corresponds to the "lower frame" in the present invention, and the sacral support bracket 42 corresponds to the "sacral support" in the present invention.

The left and right side frames 34 are formed in a long shape by, for example, press-molding a sheet metal, and are arranged with the longitudinal direction along the seat vertical direction and the thickness direction along the seat width direction. The lower end portions of the left and right side frames 34 are connected to the rear end portions of the left and right side frames 16 of the seat cushion frame 14 via the above-described reclining mechanism 26 . The reclining mechanism 26 includes a reclining rod 28 that spans between the lower ends of the left and right side frames 34 . The reclining rod 28 has a cylindrical shape whose axial direction is the seat lateral direction (seat width direction).

The upper frame 36 is formed by bending a metal pipe, for example, and has a substantially inverted U shape when viewed from the front of the seat. The upper frame 36 has the lower ends of the left and right side portions extending in the seat up-down direction fixed to the upper end portions of the left and right side frames 34 by means of welding or the like. A pair of left and right headrest support brackets 37 for connecting a headrest frame (not shown) of the headrest 56 is fixed to the upper end portion of the upper frame 36 extending in the lateral direction of the seat. Note that the upper frame 36 may be made of sheet metal.

The upper panel 38 is formed in a long shape by press-molding a sheet metal, for example, and is arranged in a posture in which the longitudinal direction is along the seat left-right direction and the thickness direction is along the seat front-rear direction. Both ends of the upper panel 38 in the left-right direction of the seat are overlapped from the seat rear side with intermediate portions in the vertical direction of the seat on left and right sides of the upper frame 36, and are fixed to the upper frame 36 by welding or the like. there is

The lower panel 40 is formed in a long shape by press-molding a sheet metal, for example, and is arranged in a posture in which the longitudinal direction extends along the seat left-right direction and the thickness direction extends along the seat front-rear direction. As an example, both ends of the lower panel 40 in the lateral direction of the seat are enlarged in height toward the upper side of the seat toward the outer side in the lateral direction of the seat. Both ends of the lower panel 40 in the lateral direction of the seat overlap the lower ends of the left and right side frames 34 from the seat rear side, and are fixed to the left and right side frames 34 by means of welding or the like. The lower panel 40 is arranged on the seat rear side with respect to the reclining rod 28 . A lower flange portion 40A is formed at the lower end portion of the lower panel 40 and has a thickness direction in the vertical direction of the seat.

As shown in FIG. 1 , a pair of left and right seat back springs 50 are bridged between the upper panel 38 and the lower panel 40 . A lumbar support plate 52 made of resin, for example, is attached to the seat front side of the left and right seat back springs 50 . The lumbar support plate 52 is arranged with the seat front-rear direction as the thickness direction, and has a substantially ladder shape when viewed in the seat front-rear direction. The lumbar support plate 52 and the left and right seat back springs 50 elastically support the pad material of the seat back 30 from the rear side of the seat, and the lumbar region of the seated person is supported from the rear side of the seat by the lumbar support plate 52. It is configured.

As shown in FIGS. 1 to 6, the sacral support bracket 42 is formed in a long shape by press-molding a sheet metal, the longitudinal direction of which extends along the lateral direction of the seat, and the thickness direction of the major portion of the bracket. It is arranged along the vertical direction of the seat. The sacral support bracket 42 includes a fixed portion 42A fixed to the lower surface of the lower flange portion 40A (see FIG. 3) of the lower panel 40, a forward extension portion 42B extending from the fixed portion 42A toward the front side of the seat, and a front It integrally has a longitudinally extending portion 42C extending upward from the front end of the extending portion 42B.

In FIG. 4, the fixed portion 42A has a long plate shape with the longitudinal direction in the lateral direction of the seat and the thickness direction in the vertical direction of the seat. The fixed portion 42A is superimposed on the lower surface of the lower flange portion 40A of the lower panel 40 from the seat lower side. As an example, a plurality of (here, eight) through-holes 44 for welding are formed in the fixing portion 42A. A plurality of weld through holes 44 are spaced longitudinally of the sacral support bracket 42 . The fixed portion 42A is joined to the lower flange portion 40A of the lower panel 40 by welding at the edge portions of the plurality of welding through holes 44 . It should be noted that the fixing portion 42A may be fixed to the lower panel 40 by means such as bolting.

The front extending portion 42B integrally extends from the front end of the fixed portion 42A toward the front side of the seat, and has an elongated shape whose longitudinal direction is the lateral direction of the seat. An intermediate portion in the seat front-rear direction of the forward extending portion 42B is a bent portion 42B1 that is a weak portion. The bent portion 42B1 is formed by bending an intermediate portion in the seat front-rear direction of the forward extending portion 42B so as to form a protrusion toward the upper side of the seat. As an example, the bent portion 42B1 has an inverted V shape when viewed in the lateral direction of the seat. A ridgeline 45 extending in the lateral direction of the seat is formed at the top of the bent portion 42B1. The forward extending portion 42B is weakened (weakened) against the load from the front side of the seat at the bent portion 42B1. A portion of the forward extending portion 42B other than the bent portion 42B1 has a plate shape whose thickness direction is the vertical direction of the seat. It should be noted that an intermediate portion in the seat front-rear direction of the forward extending portion 42B may be configured to form a bent portion by bending in a convex shape toward the seat lower side. Moreover, the bent shape of the bent portion 42B1 is not limited to the above, and can be changed as appropriate.

A bent portion 42B1 (weak portion) of the forward extending portion 42B is formed with a plurality of (here, five) through-holes 46 passing through the bent portion 42B1 in the vertical direction of the seat. As an example, the plurality of through-holes 46 have a substantially elongated rectangular shape with the longitudinal direction extending in the lateral direction of the seat when viewed in the vertical direction of the seat, and are arranged at intervals in the lateral direction of the seat. A plurality of through-holes 46 penetrate the top portion and the vertical intermediate portion of the bent portion 42B1. These through holes 46 divide the ridgeline 45 at the top of the bent portion 42B1 into a plurality of parts in the lateral direction of the seat. In addition, as shown in FIG. 4, a pair of left and right recessed portions 48 are formed at the rear portion of the bent portion 42B1 as an example. The left and right recessed portions 48 are recessed toward the front side of the seat in plan view. These concave portions 48 are formed to avoid interference with a pair of left and right convex portions (not shown) formed at the lower end portion of the lower panel 40 .

The longitudinally extending portion 42C extends upward from the front end of the forwardly extending portion 42B. An upper end portion of the vertically extending portion 42C is obliquely bent toward the seat rear side. The longitudinally extending portion 42</b>C is arranged to face the sacral portion of the person seated on the vehicle seat 10 from the rear side of the seat. The sacral part of the seated person is pressed against the longitudinally extending part 42C of the sacrum support bracket 42 via the skin 54 of the seat back 30 and a pad material (not shown), and is supported by the sacrum support bracket 42 from the rear side of the seat. Note that the longitudinally extending portion may be configured to extend downward from the front end of the forwardly extending portion 42B.

The sacrum support bracket 42 configured as described above is arranged on the seat lower side with respect to the reclining rod 28 . When an excessive load is applied to the sacrum support bracket 42 from the front side of the seat, stress concentrates on the bent portion 42B1, which is a weak portion. As a result, the sacral support bracket 42 is configured to be deformed (buckled) at the bending portion 42B1.

(Action and effect)
Next, the operation and effects of this embodiment will be described.

In the vehicle seat 10 configured as described above, the left and right side frames 34 of the seat back frame 32 extend in the seat vertical direction within the left and right side portions of the seat back 30 . A lower panel 40 spans between the rear ends of the lower ends of the left and right side frames 34 . A sacrum support bracket 42 extends forward from the lower end of the lower panel 40 . The sacral support bracket 42 supports the sacrum of the seated person from the rear side of the seat. As a result, the rocking motion of the seated person in the roll direction during normal vehicle travel is suppressed, and the seated posture is maintained. The sacrum support bracket 42 is provided with a bent portion 42B1 (weakened portion) weakened against the load from the front side of the seat. Therefore, in the event of a rear-end collision of the vehicle, the sacral support bracket 42 is deformed at the bent portion 42B1 by inputting a load from the sacral portion of the seated person to the sacral support bracket 42 . As a result, the inertial energy of the seated person is absorbed, and the moment applied to the seatback frame 32 is reduced. As a result, the occurrence of a phenomenon in which the seated occupant climbs up obliquely upward in the rear of the vehicle is suppressed, so that the seated occupant can be protected.

The above effects will be described in detail using a vehicle seat 100 (comparative example) shown in FIGS. 7 to 11. FIG. 10 and 11 show a state in which the seat back 30 is greatly tilted toward the seat rear side due to the load applied to the seat back 30 from the seated person P during a rear-end collision of the vehicle. In this vehicle seat 100, as shown in FIG. 7, the sacrum support bracket 42 is configured without a bent portion 42B1 that is a weak portion, and the entire forward extending portion 42B extends in the vertical direction of the seat. It has a plate-like shape with a direction. This vehicle seat 100 is configured in the same manner as the vehicle seat 10 according to the present embodiment except for the configuration described above.

When a vehicle in which this vehicle seat 100 is mounted undergoes a rear collision, as shown in FIG. 8, the buttocks P2 of the seated person P moving inertially toward the rear side of the vehicle move to the sacrum support bracket via the skin and pad material (not shown). 42 , and an excessive load is input to the sacrum support bracket 42 and the lower panel 40 . As a result, as shown in FIG. 9, a clockwise moment M is generated in the lower panel 40 when viewed from the left side of the seat. As a result, as shown in FIG. 10, the lower panel 40 is deformed so as to be greatly inclined toward the seat rear side (see arrow C in FIG. 10), and the lumbar support plate 52 is greatly moved toward the seat rear side with respect to the seat back frame 32. Displace. This displacement of the lumbar support plate 52 weakens the support of the waist P1 of the seated person P by the lumbar support plate 52 . At this time, as shown in FIGS. 10 and 11, the seat back 30 is greatly inclined toward the seat rear side due to the load from the seated person. It rises obliquely upward behind the seat (see arrow R in FIG. 11). Due to this rising, the input to the seat back 30 increases, and the seat back 30 further inclines toward the rear side of the seat (see arrow L in FIG. 11). Therefore, the vehicle seat 100 has room for improvement in terms of enhancing the safety of the seated person P.

On the other hand, in the vehicle seat 10 according to the present embodiment, as shown in FIG. 12, the sacrum support bracket 42 arranged behind the seat P2 of the seated person P has a bent portion 42B1 as a weakened portion. are doing. When a vehicle equipped with this vehicle seat 10 undergoes a rear collision, as shown in FIG. 13, the buttocks P2 of the occupant P inertially moving toward the rear of the vehicle move to the sacrum support bracket via the skin and pad material (not shown). 42 and the sacral support bracket 42 deforms (buckles) at the bend 42B1 (see arrow B in FIG. 13). As a result, the aforementioned moment M is not generated with respect to the lower panel 40, and the displacement of the lumbar support plate 52 with respect to the seat back frame 32 toward the seat rear side is reduced. Also, the seated person P sinks into the seat back 30 (see arrow E in FIG. 14), and the support of the waist P1 of the seated person P by the lumbar support plate 52 and the like is maintained. As a result, as shown in FIGS. 14 and 15, the seated person P is restrained from rising obliquely upward on the rear side of the seat, and an increase in the input to the seat back 30 is avoided. Therefore, in this vehicle seat 10, the safety of the seated person P can be enhanced as compared with the vehicle seat 100. As shown in FIG.

Further, in this embodiment, the sacrum support bracket 42 made of sheet metal has a fixing portion 42A and a forward extending portion 42B. The fixed portion 42A is fixed to the lower surface of the lower panel 40, and the forward extending portion 42B extends from the fixed portion 42A toward the front side of the seat. At the time of a rear-end collision of the vehicle, the bending portion 42B1 provided in the intermediate portion in the seat longitudinal direction of the forward extending portion 42B buckles due to the load from the sacral portion of the seated person P. As shown in FIG. In this way, the bent portion 42B1 (weak portion) is provided in the forward extending portion 42B of the sacral support bracket 42 made of sheet metal. is easy.

Further, in the present embodiment, the fragile portion provided in the intermediate portion in the seat front-rear direction of the forward extending portion 42B is the bent portion 42B1 that is bent to form a protrusion toward the upper side of the seat. Stress concentrates on the bent portion 42B1 due to the load from the seated person P at the time of a rear-end collision of the vehicle, and the bent portion 42B1 is deformed (buckled). In this way, since the bent portion 42B1 is the fragile portion, the fragile portion can have a simple configuration.

Further, in the present embodiment, a plurality of through holes 46 penetrating the bent portion 42B1 in the seat up-down direction are formed in the bent portion 42B1 (weak portion) provided in the intermediate portion in the seat front-rear direction of the forward extending portion 42B. formed. The deformation load of the bent portion 42B1 can be easily adjusted by changing the shape, number, etc. of these through-holes 46 .

In addition, in this embodiment, the sacrum support bracket 42 has a longitudinally extending portion 42C extending upward from the front end of the forwardly extending portion 42B. Since the sacrum of the seated person P is supported by the front surface of the longitudinally extending portion 42C, the uncomfortable feeling of the seated person P is reduced.

Furthermore, in this embodiment, a reclining rod 28 is bridged between the lower ends of the left and right side frames 34 of the seat back frame 32 . A sacrum support bracket 42 extending forward from the lower end of the lower panel 40 is arranged below the seat with respect to the reclining rod 28 . By arranging the sacral support bracket 42 at this height, the sacral part of the seated person P can be appropriately supported.

In the above-described embodiment, the fragile portion of the sacrum support bracket 42 (sacral support portion) is configured to be the bent portion 42B1, but the present invention is not limited to this. For example, the bent portion 42B1 may be omitted and the fragile portion may be weakened only by the plurality of through holes 46. FIG.

Further, in the above embodiment, the lower panel 40 (lower frame) and the sacrum support bracket 42 (sacrum support portion) are made of sheet metal, but the present invention is not limited to this. For example, a configuration in which the lower frame and the sacrum supporting portion are manufactured from metal bars or pipes may be employed.

Further, in the above-described embodiment, the bent portion 42B1, which is a weakened portion, is provided at the intermediate portion in the seat front-rear direction of the forward extending portion 42B of the sacral support bracket 42 (sacral support portion). isn't it. For example, a weak portion may be provided in the fixed portion of the sacrum supporting portion to the lower panel 40 (lower frame). In this case, for example, when an excessive load is applied to the sacrum support portion from the front side of the seat, the fragile portion may be destroyed and the sacrum support portion may drop off from the lower frame.

In addition, the present invention can be implemented with various modifications without departing from the scope of the invention. In addition, it goes without saying that the scope of rights of the present invention is not limited to the above embodiments.

REFERENCE SIGNS LIST 10 vehicle seat 12 seat cushion 14 seat cushion frame 28 reclining rod 30 seat back 32 seat back frame 34 side frame 40 lower panel (lower frame)
42 sacral support bracket (sacral support)
42A fixed portion 42B forward extending portion 42B1 bent portion (weak portion)
42C vertical extension 46 through hole

Claims (7)

left and right side frames extending in the vertical direction of the seat within the left and right side portions of the seat back of the vehicle seat;
a lower frame bridged between lower end portions of the left and right side frames;
A sacrum support provided with a fragile portion that extends from the lower end of the lower frame to the front side of the seat, supports the sacral portion of the seated person from the rear side of the seat, and is weakened against the load from the front side of the seat. Department and
seat back frame with The sacrum support portion is made of sheet metal, and has a fixed portion fixed to the lower surface of the lower frame and a forward extension portion extending forward from the fixed portion toward the front side of the seat,
The seat back frame according to claim 1, wherein the fragile portion is provided at an intermediate portion in the seat front-rear direction of the forward extending portion. 3. The seatback frame according to claim 2, wherein the fragile portion has a bent portion formed by bending an intermediate portion in the seat front-rear direction of the forward extending portion to form a protrusion toward one side in the seat up-down direction. 4. The seat back frame according to claim 2, wherein the fragile portion is formed with a through hole penetrating the fragile portion in the vertical direction of the seat. The seatback frame according to any one of claims 2 to 4, wherein the sacral supporting portion has a longitudinally extending portion extending from the front end of the forwardly extending portion to one side in the vertical direction of the seat. A reclining rod is bridged between the lower ends of the left and right side frames,
The seat back frame according to any one of claims 1 to 5, wherein the sacrum support portion is arranged on the seat lower side with respect to the reclining rod. a seat cushion having a seat cushion frame;
a seatback having the seatback frame according to any one of claims 1 to 6, wherein the lower ends of the left and right side frames are connected to the rear end of the seat cushion frame;
A vehicle seat with

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